Реферат: Using the p-TREF method, data were obtained on the effect of the composition of Ziegler-Natta catalytic systems on the content of individual PP fractions with different isotacticity , which are formed on the active sites of these catalysts with different stereospecificity. Data on the molecular weight and thermophysical characteristics of these fractions are presented. Based on the data obtained on the effect of the composition of titanium-magnesium catalysts on the content of individual polypropylene fractions with different isotacticity, two schemes for the formation of active sites with different isospecificity in TMC are proposed. In the first scheme, the key structure is a mononuclear Ti3+ compound attached to the lateral face (110) of the MgCl2 support and acting as a non-stereospecific active AS site. In the second scheme, such a structure is a binuclear compound Ti3+ fixed on the face (104) of the MgCl2 support. In both cases, the transformation of AS sites into active sites of IS1, IS2, and IS3 with different isospecificity occurs as a result of adsorption of an organoaluminum compound, an internal or external stereoregulating donor on magnesium ions on the neighboring atom close to the Ti3+ ion in the active AS site, or on a non-alkylated Ti3+ ion in the binuclear structure of the active site.

Библиографическая ссылка: Matsko M. , Zakharov V.A. , Barabanov A.A.
Application of Preparative Fractionation of Polyolefins for Analysis of Heterogeneity of Active Sites of Ziegler-Natta Catalysts
9th International Conference of Polyolefin Characterization 10-12 Nov 2025